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Short Discharge Time

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jan_de_jong(at)casema.nl
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Posted: Sun Feb 03, 2013 2:38 am Post subject: Short Discharge Time

Batteries!

With batteries there are 2 properties of interest:

1. the energy content measured in Wh, or Ah x voltage at some standard 

rate of discharge.

2. the efficiency of release of the energy (some power rating)

The first measure is fairly well established, although the "standard" 

discharge rate is often very low or not even mentioned, but the second 

is not. Manufacturers may give a power rating in W, but they do not 

mention how much power is lost internally in heat and what temperature 

increase for the battery they had to consider still within bounds to 

attain the given power rating.

Manufacturers may also give an internal resistance but it may be at a 

useless 1 kHz. In any case it must be related to capacity and voltage to 

decide whether the number is relatively high or low.

Mr. Davide Andrea introduces the "Short Discharge Time" (a calculated 

time in seconds to completely discharge a battery if shorted) as a 

figure of merit for battery efficiency. It does not depend on size, 

voltage and composition of a battery.

I found the following interesting:

http://liionbms.com/php/wp_short_discharge_time.php



Jan de Jong

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mrspudandcompany(at)veriz
Guest

Posted: Sun Feb 03, 2013 6:07 am Post subject: Short Discharge Time

 	  Quote: 	
		   Batteries!

 With batteries there are 2 properties of interest:

 1. the energy content measured in Wh, or Ah x voltage at some standard 

 rate of discharge.

 2. the efficiency of release of the energy (some power rating)


	


        May I add a third property of interest?

        3.  Batteries that self ignite for some unknown reason should never 

be used in an aircraft, even

        if they meet or exceed all of another batteries specs!



        Roger 

--



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jan_de_jong(at)casema.nl
Guest

Posted: Sun Feb 03, 2013 12:00 pm Post subject: Short Discharge Time

I might have said: there are two functional properties of interest - and 

a host of non-functional ones - of which not conflagrating ranks pretty 

high indeed.



Jan de Jong



On 2/3/2013 3:06 PM, R. curtis wrote:

 	  Quote: 	
		   

 <mrspudandcompany(at)verizon.net>



> Batteries!

> With batteries there are 2 properties of interest:

> 1. the energy content measured in Wh, or Ah x voltage at some 

> standard rate of discharge.

> 2. the efficiency of release of the energy (some power rating)



        May I add a third property of interest?

        3.  Batteries that self ignite for some unknown reason should 

 never be used in an aircraft, even

        if they meet or exceed all of another batteries specs!



        Roger

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Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

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